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GD News
GD-Statement
Potential of Occlusion by liquid Paraffin
in Cosmetics
The use of liquid paraffin (INCI: paraffinum liquidum) as lipid ingredient
in cosmetic preparations for skin care is subject to a controversial discussion
in parts of the population. The reason for the reservation is the peril
of an occlusion (masking) for applications of liquid paraffin in certain
concentrations, for example more than 10 percent of the lipid phase.
The complete occlusion
by a steam impermeable layer, for instance by a plastic foil at the skin
surface may according to scientific insights in fact lead to an impairment
of the reproduction and maturation as well as of the metabolism of the
skin cells in the epidermis and as a consequence to a barrier disruption
in the horny layer of the epidermis [1-4]. However, this unwanted effect
is not to be expected at uses of cosmetics as directed [5]. Only a certain,
occlusive effect, limited in time, is possible. The extent of such a partial
occlusive effect is determined by:
1. Type of the base, e.g. pure oil, anhydrous greasy ointments, water-in-oil
or oil-in-water emulsions (stated according to decreasing occlusivity)
2. Kind and quantity of the lipids applied
3. Other additives
as spreading agents or emulsifiers
4. Product quantity
applied and spreading on skin by rubbing
Accordingly, the sole information about the proportion of liquid paraffin
in the oil phase does not allow a qualified judgement of an occlusive
effect. This is rather only possible by dermatologically controlled application
tests by measuring of skin physiological parameter with bio-engineering
methods, e.g. in form of a proof as to a significant reduction of TEWL
shortly after application [6].
There is no evidence
according to latest scientific findings for a corresponding risk of unwanted
effects of cosmetics, containing more than 10 percent of liquid paraffin
in the oil phase. Referring to this assessment criterion it is a question
of a rough simplification which does not give any information about the
actual risk profile of a cosmetical product.
Irrespective of this fact, a certain occlusive effect is wanted in many
cases, thus for example with dry, barrier-impaired skin, in the field
of baby care or at applications of skin protection ointments in the professional
sphere [7].
References
[1] Fluhr JW, Lazzerini S, Distante F, Gloor M, Berardesca E: Effects
of prolonged occlusion on stratum corneum barrier function and water holding
capacity. Skin Pharmacol. Appl. Skin Physiol. 12 (1999) 193-198
[2] Proksch E: Lipide der Hornschicht: Analyse, Regulation, Funktion.
In: Klaschka, F. (Hrsg.): Empfindliche Haut. Diesbach Verlag Berlin, S.
(1992) 12-21
[3] Proksch E, Feingold K, Mao-Quiang M, Elias PM: Barrier function regulates
epidermal DNA synthesis. J. Clin. Invest. 87 (1991) 1668-1673
[4] Taljebini M, Warren R, Mao-Quiang M, Lane E, Elias PE, Feingold KR:
Cutaneous permeability barrier repair following various types of insults:
kinetics and effects of occlusion. Skin Pharmacol. 9 (1996) 111-119
[5] Ghadially R, Halkier-Sorensen L, Elias PM: Effects of petrolatum on
stratum corneum structure and function. J. Amer. Acad. Dermatol. 26 (1992)
387-396
[6] Jemec GBE, Serup J: Epidermal hydration and skin mechanics. The relationship
between electrical capacitance and the mechanical properties of human
skin in vivo. Acta Derm. Venereol. (Stockh.) 70 (1990) 245-247,
[7] Maibach HI: Barrier creams (skin protective creams). Cosmet. &
Toiletr. 6 (2000) 30-34
GD
statements are official position papers of the society established
by the departments or other GD experts and approved for publication
by the GD managing committee. Both statements relating to the Potential
of a Penetration Effect by PEG-compounds respectively Occlusion by
Liquid Paraffin in Cosmetics have been elaborated by the department
Dermocosmetics and already placed at the disposal of the sponsoring
GD member firms in August 2001. |
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